Plug for an atomic reactor channel



July 14, 1964 D. cos-res 3,140,730

' PLUG FOR AN ATOMIC REACTOR CHANNEL Filed Aug. 3, 1962 2 Sheets-Sheet 1July 14, 1964 D. COSTES PLUG FOR AN' ATOMIC REACTOR CHANNEL 2Sheets-Sheet 2 Filed Aug. 3, 1962 7 EEK/ INVENTOR.

Us sm B F Ill! u N .ws a 2 United States Patent 9 3,140,730 PLUG FOR ANATOMIC REACTOR CHANNEL Didier Costes, Paris, France, assignor toCommissariat a lEnergie Atornique, Paris, France Filed Aug. 3, 1962,Ser. No. 214,632 Claims priority, application France Aug. 16, 1961 11Claims. (Cl. 138-89) In atomic reactors, it is frequently necessary toclose the ends of channels or tubes containing a fluid under pressure byplugs which must:

Be impervious to the fluid and sufficiently durable;

Be capable of manipulation by special machines, particularly for theloading and the unloading of the channels with nuclear fuel, withoutmanual intervention because of the radiations emitted by this fuel andwith appreciable off-centre tolerances;

Not allow incorrect operations and, particularly during themanipulations of fuel, being adapted for removal only when the loadingmachine is fitted to the channel of the plug under consideration.

According to the present invention there is provided a plug for anatomic reactor channel comprising a latching means for co-operation witha loading and unloading machine, provided with a conveyor elementadapted to be engaged into said channel and onto which the plug can belatched, and a control element adapted to actuate the said latchingmeans while being displaced relatively to the conveyor element, saidplug comprising in addition to a member ensuring the actual closing ofthe channel in which it is mounted, a first set of latching members forensuring the connection of the plug to the conveyor element of themachine, a second set of latching members for ensuring the fixing of theplug on the wall of the reactor channel, an operating member cooperatingwith the control element of the machine and movable in the plug bodybetween two extreme positions, one of which corresponds to the latchedposition of one of the sets of latching members and to the unlatchedposition of the second set of latching members, and the other to theopposite positions of these same latching members, and mechanicalconnecting means between the two sets of latching members, such thatwhen one of the sets of latching members is latched in one of theextreme positions of the movable operating member, the other set ofthese latching members is unlatched.

The latching members belonging to the two aforesaid sets areadvantageously formed by catches or hooks which are pivoted on pins(parallel or perpendicular to the general axis) carried by the plug andwhich cooperate with grooves formed respectively in the channel wall andin the conveyor element of the machine, this latter element preferablybeing of tubular form, the complete arrangement being such that all thehooks or catches remain engaged at least partially in their respectivegrooves when the operating member occupies an intermediate position.

As regards the operating member, it is preferably formed by a rodmounted so as to be able to slide in the plug along the general axis andshaped as a cam for the two sets of latching members. In order to avoidthe resilient wear in the said grooves disturbing the operation of thecatches or books, the operating member is designed in such a Way that itacts on these latter in an irreversible manner in the only directioncorresponding to their engagement in the corresponding groove and apositive mechanical connection is interposed between the two sets oflatching members in order that the controlled displacement of thecatches or hooks of one set in the aforesaid direction causes thedisplacement of the catches or hooks of the other set in the oppositedirection.

estates Patented July 14, 1964 The invention will now be described byway of example with reference to the accompanying drawings, wherein:

FIG. 1 is a partial front sectional view of a channel plug according tothe invention and also of the conveyor elements and control elements ofa loading and unloading machine.

FIGS. 2, 3 and 4 are respectively transverse sections along the linesIIII, III-III and IV-IV of FIG. 1.

FIG. 5 is a partial front sectional view of another channel plugaccording to the invention, as well as of the elements of a machineadapted to extract and replace the said plug.

FIG. 6 shows the plug according to FIG. 5 in another operationalposition.

The plug according to the invention is adapted for shutting off thechannels of a nuclear reactor, said channels containing fuel elements.FIG. 1 shows the end portion 2 of such a channel which is normallyclosed by the plug body 11 and which has a terminal flange l3 fittedexternally with fluid-tight seals 50.

The loading and unloading machine for such channels comprisesessentially:

A conveyor element in the form of a tube 17, this tube having an end 23which is conical on the outside and is provided on the inside with alatching groove 17a;

A control element formed by an internal rod 18 which carrieslongitudinal fins 24 and, at its end, a tubular member 63 fixed on thefins 24, the said element comprising tongues 35, the ends 70 of whichare formed as hooks;

And an intermediate tube 47 which is connected in fluid-tight manner tothe interior of the machine by means enabling its end 47a to carry outaxial or radial displacements and which carries at the forward end aconical or spherical opening 49 adapted to co-operate with the annularprojection 13.

The machine is arranged in such a way as to be able to approach or moveaway from the tube assembly 17 and 47 and the rod 18 axially of thechannel, to cause the rod 18 to slide inside the tube 17 and the ends"ill of the tongues to move away or approach one another radially.

As regards the plug, the body 11 thereof is provided with a detachablepart 83, which carries a first set of catches 84 co-operating with agroove 85 formed in the channel and a second set of hooks S6co-operating with the said groove 17a of the tube 17, the catches 84-and hooks 86 being equal in number (for example three, as shown in FIGS.2 and 4). In addition, a single operating member formed by a sliding rod$7 is mounted in the element 83, the said rod being provided with abulged or thickened portion 88 and carries a washer 89 on its rearwardportion. This washer is formed with an internal groove 99 in which theends 79 of the tongues 36 are adapted to engage.

The thickened portion 88 of the rod 87 operates in the sense of actingon the one hand on the catches 84 by contact with a surface 84a of thelatter and on the other hand on the hooks 86 by contact with the keys orarms 91. The catches 84, the hooks 86 and the arms 91 are pivoted on theplug by means of pins @2 which are parallel to the general axis and withwhich they are made fast, for example by splines or dowels, these pinsthus constituting a positive mechanical connection between the catches84 and the hooks 86 and also with the arms 91.

The rod 87 is equipped with a locking device formed by catches 93,co-operating with a groove 94 formed on the periphery of the rod 87,these catches each being actuated by a feeler member 95. Each feelermember 95 is urged by a spring 96 which tends to engage thecorresponding catch 93 in the groove 94 and its end is disposed on thetrajectory of the tube 17 of the machine so that it disengages the catch93 when this tube occupies the desired operative position shown inFIG. 1. The centering of the tube 17 on the plug is facilitated by aring 97 with a profiled inlet, this ring preferably being screwed on themember 83.

In order to determine the exact position of the plug 11 whichcorresponds to the positioning of the catches 84 opposite the groove 85,the plug is formed with a first shoulder 98, for example at theconnection between the rear part 83 and the plug body, by providing onthe end of the channel, in order to form an abutment, a correspondingchange in section between two parts 99 and 106 of the channel. Inaddition, in order to improve the fluid-tight conditions of the plug, itis possible on the one hand to provide the latter with a second shoulder101 by forming a detachment M2 by a change in section between the twoparts of the channel 101) and 2, but this time by positioning thedetachment or incline 1% in such a way that it does not form an abutmentfor the shoulder 101 of the plug, and on the other hand to arrange onthe plug fluid-tight joints 163 in a cylindrical portion comprisedbetween the shoulders 93 and 101, the part 1111? of the channelco-operating with these joints being carefully machined.

In the case where the fluid-tightness would be assured not by joints 1%formed between cylindrical portions, but by a bearing of the plugagainst a fluid-tight seating (similar for example to the bearing of theshoulder 93 against the corresponding shoulder of the channel), thecatches 34 can comprise sloping bearing surfaces 104 (FIG. 4), theelasticity necessary in order that the rod 87 can reach the forward endof its travel being provided by plungers 105 loaded by springs 106interposed between the catches 84 and the thickened portion 88 of therod. The slant angle of the surfaces 104 is then determined so that theanchoring cannot be cancelled out under the effect of an axial thrustexerted on the plug from inside the channel.

The operation of the plug according to the invention is as follows:

Under normal conditions, that is to say, when the assembly of the tubes17 and 47 and the rod 13 is spaced apart, the rod 87 occupies theposition illustrated, in gvhich it is locked by the catch 93 engaged inthe groove The catches 84 are themselves engaged in the groove 85 of thechannel, while the hooks 86 are displaced inwardly. The plug is bearingby means of its shoulder 98 and the fluid-tightness of the channel isassured by the joints 103.

When it is desired to withdraw the plug, the tube 47 is moved axiallyforwards, this tube being centered on the annular projection 13 and thejoints 5*?) ensure a fluid-tight communication between the reactorchannel and the inside of the machine. The tube 17, the conical end 23of which is centered on the ring 97, is then moved forward and, when thetube reaches the end of its travel, it causes the feeler member 95 torock, thus unlocking the rod 87. The rod 18 is then moved forward andthe tongues 36 are actuated in such a manner that their ends 70 areengaged in the groove 90 of the washer 89, and then the rod assembly 18and S7 is retracted. The thickened portion 88, in passing over themembers 91, causes the pivots 92 to turn, and this first of all engagesthe hooks 86 in the groove 17:; of the tube 17, and then on completionof the movement extracts the catches 84 from the groove 85. By asimultaneous retraction of the rod 18 and the tube 17, it is thenpossible to extract the plug inside the tube 47, the end 23 of the tube17 being engaged in said plug and the latter being locked with said tubeby the hooks 86.

Once the plug is separated inside the loading machine from the assemblycomprising the tube 17 and the rod 18, it is possible to press thislatter inside the channel in order to find the protective shells and thefuel elements which line this channel, and it is to be noted that thepossibly off-centre end 23 capable of contacting the tube 47 by itsportion of maximum diameter is not able, because of its conicity, tocontact that part of the channel 1% which ensures fluid-tightness, norits entry shoulder 98, but only the portion 2 of smaller diameter, afterhaving possibly struck the shoulder 102 which does not contribute to thefluid-tightness.

According to a modification of the invention as shown in FIGURE 5, theplug is formed by an internal element or body 11 and by an externalelement 83 following one another axially of the extreme portion 2 of thechannel and capable of a limited relative displacement in thisdirection, the element 83 being provided with a mechanism capable ofimmobilising it in the channel in which the plug is forced, and the twoelements are operated in such a way that together they define aperipheral groove 1G7 adapted to receive a resilient ring 108, theassembly being such that the thrust exerted on the body 11 by the fluidunder pressure contained in the channel section 2 when the externalelement 33 is immobilised by the aforesaid mechanism axially contractsthe ring 1% while expanding it radially against the Wall of the channel.

The groove 107 is limited internally by the periphery of a cylindricalprojection 109 fast with one of the elements (for example the element83) th s projection being adapted to slide with a small radial clearancein a bore 111) formed in the other element (in the present case, thebody 11). The said periphery is polished and possibly lubricated so thatthe internal cylindrical wall of the ring 198 is able to slide thereon.

The groove 107 is limited axially by two parallel plane surfaces 11a and83a belonging respectively to the elements 11 and 83. Known meansprevent the extrusion of the material of the ring M8 (for examplenatural or synthetic rubber) into the gap which corresponds to theradial clearance existing between the projection 109 and the bore 119.The internal edge of the ring 108 near this gap is for example given aradius of curvature conforming to the hardness of the material of thesaid ring or a harder ring 111 is interposed at this position.

In order to limit the relative axial spacing of the elements 11 and 83,the ring 198 is sealed with the surfaces 11a and 83a. and/or a rigidstop is interposed between these elements. The latter is for exampleformed by an axial rod 112 screwed into the body 11 and having a head112a cooperating with an internal shoulder 10911 of the projection 189.

According to another modification of the invention as shown in FIGURE 6,the two elements 11, 83 are advantageously provided with mechanicalmeans enabling them to approach one another axially when there is nofluid under pressure in the channel section 2. These means may be formedby a movable threaded tie rod 113, shown in chain-dotted lines in FIGURE6, which is adapted, after being manually positioned, of bearing withits head against the external end of the element 83, of extendingcompletely through this element and especially its projection 1G9 and ofbeing screwed on to an internal thread 114 formed in the body 11. Aswill be seen, this tie rod extends freely through the rod 112, which ishollow.

It is understood that the projection 109 permits the passage of the tierod 113 without the latter touching the ring 108. It forms a common axisfor the elements 11 and 83. By modifying its external diameter, it ispossible to determine the value of the surface of the ring 1&3perpendicularly of the axis, which corresponds to the fluid-tightnesspressure desired at the contact of the ring 108 with the Wall of thechannel section 2, taking into account the pressure of the fluidcontained in this channel and the material of the ring. As shown in thefigures, it is desirable to form the projection 109 on an independentpart of the element 83 and made fast with the latter, preferably byscrew-threading.

In order to avoid the parts which it is necessary to cause to slide inthe channel damaging the contact surface between the wall of the channeland the ring 108, it is possible to provide a very shallow groove 115 onthe said wall at the required axial position. When the ring 108 is notcompressed, the external surface is slightly withdrawn from thecylindrical surface enveloping the plug, so that there is no risk ofdamage thereto during the manipulations.

The body 11 is advantageously provided with a scraper ring 116 offlexible material, such as synthetic rubber, which provides a suflicienttightness between the said body and the wall of the channel to ensure areturn movement of this body such that the ring 108 is expanded radiallyuntil in contact with the surface or groove 115, under the elfect of theexcess pressure which obtains in the channel relatively to theatmospheric pressure or to the lock chamber during release of theunloading machine, to which reference has been made above. The scraperring 116 has grooves 116a adapted to collect the dust which it meets onthe wall of the channel section 2. The external element 83 is similarlyprovided with a scraper ring 117 having grooves 117a. for receivingdust, but contrary to the ring 116, this does not have to befluid-tight. The groove 117a situated at the front of the ring 117 issubjected to the same pressure as the exterior of the plug, because of aduct 118 communicating with the axial passage through which the tie rod113 is adapted to extend.

As in the embodiment shown in FIGURES 1 to 4, the latching mechanism ofthe element 83 of the plug can comprise a catch 84 pivoted on theelement 83 and adapted to be urged into a groove 85 formed in the wallof the channel section 2 by a thickened portion 88 on the sliding rod87a. In the constructional form shown in FIGURE 6, this rod is hollow inorder to permit the pas sage of the threaded tie rod 113 and carries awasher 89 formed with a groove 99.

The manipulation of the plug is carried out as follows:

With the loading machine connected to the channel and with the fluidpressure being substantially uniform in the lock chamber and thechannel, the plug is placed in position, after having retracted thecatches 34 by the rod 87 being pulled outwardly by means of the rod 18(position shown in FIGURE 5), after which these catches are engaged inthe groove 85 (position shown in FIG URE 6) by again pushing the rod87a. With the element 83 thus immobilised, the pressure in the lockchamber is reduced. The element 11 is pushed outwardly (as indicated bythe arrow F, in FIGURE 6) by the fluid under pressure contained in thechannel and retained by the scraper ring 116, thus axially contractingthe ring 198 and expanding it radially, thus pressing it into the groove115. The plug then closes the channel in a fluidtight manner.

If the channel is to be placed under vacuum, for example, in order toenable the reactor circuits to be correctly filled with cooling fluid,the tie rod 113 is introduced manually, as shown in chain-dotted linesin FIG URE 6, and the ring 108 is contracted axially with the sameeffect as in the preceding case, but this time by screwing the said tierod in the screwthread 114. The head of the tie rod bears on the element83 by means of the washer 89.

As will be obvious and as is moreover already apparent from theforegoing, the invention is not limited in any way to that of itsmethods of application or to those of the constructional forms of itsvarious parts which have been more especially envisaged, but on thecontrary covers all modifications.

What is claimed is:

1. In combination, a nuclear reactor channel, a plug for said channel,said plug comprising a body for closing said channel, a conveyorelement, latching means on said plug cooperating with said conveyorelement for engagement with said channel and for latching said plug tosaid conveyor element, a control element for actuating said latchingmeans during displacement relative to said conveyor element, saidlatching means comprising a first set of latching members for connectingsaid plug to said conveyor element, a second set of latching members forsecuring said plug to said reactor channel and mechanical connectingmeans between said two sets of latching members so constructed andarranged that when one set of said latching members is latched saidother set of latching members is unlatched, and an operating membercooperating with said control element and movable in said plug bodybetween two extreme positions, one of said positions corresponding tothe latched position of one of said sets of latching members and to theunlatched position of the other of said sets of latching members, andthe other of said positions corresponding to the opposite positions ofsaid sets of latching members.

2. In the combination described in claim 1, said latching memberscomprising latching catches, pins carried by said plug, said latchingcatches being pivoted on said pins and grooves in said channel and insaid conveyor element receiving said catches.

3. In the combination described in claim 1, said latching memberscomprising latching hooks, pins carried by said plug, said latchinghooks being pivoted on said pins and grooves in said channel and in saidconveyor element receiving said hooks.

4. In the combination described in claim 1, said operating membercomprising an operating rod slidably mounted in the longitudinal axis ofsaid plug and a cam profile on said rod positively cooperating with eachof said two sets of latching members.

5. In the combination described in claim 1, means for locking saidoperating member with respect to said plug body in one of said extremepositions of said operating member when said plug is secured to saidreactor channel.

6. In the combination described in claim 1, said plug member comprisingan external element and an internal element disposed one after the otherin the longitudinal axis of said plug member, said external elementcarrying said latching members, means for limiting the movement of saidinternal element with respect to said external element and a deformableresilient ring between said external and internal elements and incontact with said channel when said external element is moved towardsaid in ternal element and when said external element is secured to saidchannel.

7. In the combination of claim 6, said operating member being tubular.

8. In the combination of claim 7, mechanical means extending throughsaid tubular operating member for relative movement of said external andinternal elements.

9. In the combination of claim 6, a cylindrical projection on saidexternal element and a bore in said internal element receiving saidprojection, said resilient ring surrounding said projection.

10. In the combination of claim 6, a scraper ring and a fluid-tightjoint in said plug member disposed on each side of said resilient ring.

11. In the combination described in claim 6, a sealing ring in said plugmembers disposed on each side of said resilient ring.

No references cited.

1. IN COMBINATION, A NUCLEAR REACTOR CHANNEL, A PLUG FOR SAID CHANNEL,SAID PLUG COMPRISING A BODY FOR CLOSING SAID CHANNEL, A CONVEYORELEMENT, LATCHING MEANS ON SAID PLUG COOPERATING WITH SAID CONVEYORELEMENT FOR ENGAGEMENT WITH SAID CHANNEL AND FOR LATCHING SAID PLUG TOSAID CONVEYOR ELEMENT, A CONTROL ELEMENT FOR ACTUATING SAID LATCHINGMEANS DURING DISPLACEMENT RELATIVE TO SAID CONVEYOR ELEMENT, SAIDLATCHING MEANS COMPRISING A FIRST SET OF LATCHING MEMBERS FOR CONNECTINGSAID PLUG TO SAID CONVEYOR ELEMENT, A SECOND SET OF LATCHING MEMBERS FORSECURING SAID PLUG TO SAID REACTOR CHANNEL AND MECHANICAL CONNECTINGMEANS BETWEEN SAID TWO SETS OF LATCHING MEMBERS SO CONSTRUCTED ANDARRANGED THAT WHEN ONE SET OF SAID LATCHING MEMBERS IS LATCHED SAIDOTHER SET OF LATCHING MEMBERS IS UNLATCHED, AND AN OPERATING MEMBERCOOPERATING WITH SAID CONTROL ELEMENT AND MOVABLE IN SAID PLUG BODYBETWEEN TWO EXTREME POSITIONS, ONE OF SAID POSITIONS CORRESPONDING TOTHE LATCHED POSITION OF ONE OF SAID SETS OF LATCHING MEMBERS AND TO THEUNLATCHED POSITION OF THE OTHER OF SAID SETS OF LATCHING MEMBERS, ANDTHE OTHER OF SAID POSITIONS CORRESPONDING TO THE OPPOSITE POSITIONS OFSAID SETS OF LATCHING MEMBERS.